1. Field of the Invention
This invention relates to a tamper-proof container. More specifically, the invention relates to a spin welded, thermoplastic, resealable container, where an opening is formed by separating a predetermined part of the container, and the separated part becomes a tight-sealing closure.
2. Description of the Prior Art
Ever since the cyanide-laced Tylenol capsule caused a death in 1982, tamper-evident packaging became necessary and mandatory for some consumer products. Many tamper-evident systems have been proposed and many new systems have been introduced to market. More popular, tamper-evident, resealable packaging can be divided into two general types: ones which involve mainly modification of conventional closures, and others which involve additional layers of packaging.
The first type includes closures with built-in, break-away, perforated neck bands. These require a slight modification in the neck of conventional bottles but very little modification on the existing filling and capping equipment. Vacuum safety buttons and oxidative color indicators are other examples of this type. These systems require no modification to the bottles but require packaging in a vacuum or inert atmosphere and gas-tight caps. Unless vacuum or inert gas provides other benefits, such as the improved preservation of the contents, these requirements are very costly. This type of resealable, tamper-evident container, especially one with a neck band, is economical for containers with a small opening such as bottles, but totally impractical for containers with a larger opening.
The second type includes an external shrink wrap, and an internal, flexible membrane lidding of the mouth of a bottle. Some shrink wraps cover the whole container, but most cover only critical portions of package, such as the neck of a bottle. The internal lidding has the distinct disadvantage of not being seen before the cap is opened. In general, these tamper-evident containers involve additional parts or processes. Although these systems allow one to utilize the existing containers and packaging systems, the additional steps and parts increase total cost of packaging. Since the packaging industry is mature and capital-intensive, all of the proposed tamper-evident packaging systems confine themselves to the utilization of existing packaging equipment and their simpler modification. This self-imposed restriction is self-serving and not necessarily beneficial to the consumer. Furthermore, these tamper-evident packages can in fact be tampered with. Shrink wrap stretches enough to be removed and break-away bands can be made to override the locking teeth.
On the other hand, more tamper-proof packages are not generally resealable, because to open these packages, one must cut or tear away a portion of the packaging material which is designed to be discarded. The best example is a metal can, which is the most tamper-proof package, but not resealable. For peanuts and other similar products which are removed little at a time, separate, tight-fitting plastic covers are provided for the contents. Blister packs are other popular tamper-proof or resistant package, but they are very difficult to reseal. In the majority of packaging, wed not use all of the contents at once and thus, resealability is essential. It is obvious that we need the safety of tamper-proof packaging with the convenience of resealability.